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Houdini_15a_x64:

    1) d=33 +0.12 20.Qd1 Ncd7 21.Bd3 Rc7 22.Nc3 a6 23.Bf5 exd4 24.Ne2 g6 25.Bb1 a5 26.Bd3 Nc5 27.Nxd4 Rxe1 28.Rxe1 Nxd3

    2) d=33 +0.00 20.Qf5 Bc8 21.Bxf6 Bxf5 22.Bxd8 Bxb1 23.Rxb1 exd4 24.b3 Nxb3 25.Rxb3 Rxe2 26.Bh4 Rc3 27.Rb5 Rxa3 28.Re1 Rd2

    1) <d=34 +0.10>* 20.Qd1 Ncd7 21.Bd3 Rc7 22.Nc3 a6 23.Bf5 exd4 24.Ne2 g6 25.Bb1 a5 26.Bd3 Nc5 27.Nxd4 Rxe1 28.Rxe1 Nxd3

    2) d=34 +0.00 20.Qf5 Bc8 21.Bxf6 Bxf5 22.Bxd8 Bxb1 23.Rxb1 exd4 24.b3 Nxb3 25.Rxb3 Rxe2 26.Bh4 Rc3 27.Rb5 Rxa3 28.Re1 Rd2

Here is the best line I've found so far that features <19...Ra5>

<19.Qd1 Ra5 20.Bxa6 Rxa6 21.a4 e4 22.Nc3 <exf3> 23.Qxf3 Rxe1 24.Rxe1 Qc8 25.b3 b5 26.axb5 Re6 27.Nxd5 Nxd5 28.Qxd5 Nb6 29.Qf3 Rxe1+ 30.Bxe1 Qe8 31.Bb4 Qxb5 >

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I suppose this is drawish. Note: I think 22...exf3 is preferable to the immediate 22...Qc8.

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<Critter 1.2: [+0.00], d=26, PV #2:> 20.Nc3 b5 21.dxe5 Nxe5 22.Qd4 Qb8 23.Bg3 Rae6 24.Nxd5 Nxd5 25.Qxd5 Qb6+ 26.Bf2 Qb8 27.Bg3

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<27.Bg3> After a near transposition to PV #1, Critter is apparently heading towards a draw by repetition.

<Komodo 3.0, [+0.01], d=26, PV#4>: 20.Nc3 b5 21.Qf2 Rae6 22.Nxd5 g5 23.Nxf6+ Qxf6 24.Bg3 exd4 25.Rxe6 <fxe6> 26.Qe2 a6 27.Qe4 e5 28.Rc1 Nf8 29.Rc6 Re6 30.Rc8 Kg7 31.h4 Ng6 32.Rc7+ Ne7 33.Rc5 Nc6 34.Rd5 Re7 35.b4 Kg8 36.<Rc5>

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<25...fxe6> An interesting and possibly questionable choice by Komodo. Instead of a rook on an open file it prefers a backward pawn which, however, can advance and protect the passed pawn on d4. But White can now focus on attacking this backward pawn.

<36.Rc5> Pretty much even and likely headed for a draw by repetition after 36...Re6 37.Rd5 Re7. White's pieces can't penetrate Black's position and Black's backward Pe5 is adequately protected.

<Spike 1.4: [+0.26], d=34, PV #1:> 20.Nc3 b5 21.<Nxb5> Qb6 22.Nc3 Rb8 23.Bf2 exd4 24.Qd3 Qa5 25.Na2 Nc5 26.Qxd4 Ne6 27.Qd3 <Re8> 28.Nb4 Rd6 29.Bd4 Nd7 30.Rf2 <Rc8> 31.Rc2 Rxc2 32.Nxc2 Qc7 33.Bf2 a5 34.b4 <Nf6> 35.b5 Qc4 36.Rd1 <Qxd3> 37.Rxd3 Nf4 38.Bg3 Nxd3 39.<Bxd6>

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<21.Nxb5> Unlike Critter and Komodo, Spike accepts the offered pawn. Nice to see an alternative approach, particularly an apparently successful one indicating that we have work to do.

<27...Rd8> White has come out of the maneuvering with the better position. Black has a blockadable (word?) IQP and its queen and rook are uselessly occupying the a-file. White has activated its bishop, is ready to occupy the c-file, and ready to start attacking the IQP by Nb4. Black should have considered either 27...Rd8 instead to try to advance the d-pawn or 27...Rc6 to try to grab the c-file before White can prevent that with Nb4. So, if GMVA decides to take the offered Pb5, we need to find an improvement in this line.

<30...Rc8> Showing that 27...Re8 was a wasted move. Had the rook been on c8, then 30...Rc4 would have forced the bishop to move, and 31...d5 could have followed. Then 32...Ne4 would have forced the queen to move and all of a sudden White's pieces are in full retreat and the d-pawn is ready to advance again. Passed pawns must be pushed!

<34...Nf6> IMO 34...axb4 was better. White gets a passed b-pawn regardless, but now it can be protected by the a-pawn. And Black has to constantly be on guard to protect it’s a-pawn.

<36...Qxd3> Apparently Spike's evaluation function doesn't indicate that you should avoid exchanging pieces when you have an isolated pawn. And Spike does this twice in succession!

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Analysis by Stockfish 2.0.1 JA 64bit (30-ply):

1. = (0.00): 21...d4 22.Ne4 Re6 23.Bxf6 gxf6 24.f4 Nc4 25.Qd3 b5 26.Nc5 Rxe1 27.Rxe1 Rc6 28.b4 f5 29.Qxf5 Ne3 30.Qe4 Rg6 31.g3 Qc8 32.Rc1 Qh3 33.Nb3 Rxg3+ 34.hxg3 Qxg3+ 35.Kh1 Qh3+ 36.Kg1 Qg3+

2. = (0.00): 21...Nc4 22.Qd3 Ra5 23.Bxf6 gxf6 24.Rxe8+ Qxe8 25.Nxd5 Qe5 26.Nxf6+ Qxf6 27.Qxc4 Qxb2 28.Rd1 Kg7 29.Rd7 Qa1+ 30.Kf2 Qb2+ 31.Kg1

3. = (0.00): 21...b5 22.Qd4 Qb8 23.Nxd5 Nxd5 24.Qxd5 Rd6 25.Qc5 Rde6 26.Bg3 a6 27.Qd4 Qc7 28.b3 Qe7 29.Rxe5 Rxe5 30.Bxe5 Qxe5 31.Qxe5 Rxe5 32.Kf2 Rc5 33.Re1 Kh7 34.b4 Rc2+ 35.Re2 Rc3 36.Re3 Rc2+ 37.Re2

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Analysis by Stockfish 2.0.1 JA 64bit (29-ply):

1. = (0.00): 22.Ne4 Re6 23.Bxf6 gxf6 24.Qxh6 Ra5 25.Nf2 d3 26.Rd1 f5 27.Qf4 Rd5 28.Qxf5 d2 29.Qc2 b5 30.b3 Rc6 31.Qe4 Re6 32.Qc2

2. = (0.00): 22.Rd1 Nc6 23.Nb5 Ra5 24.Nxd4 Nxd4 25.Qxd4 Qxd4+ 26.Rxd4 Re2 27.Rd8+ Kh7 28.Rf2 Re1+ 29.Rf1 Re2

3. = (0.00): 22.Bxf6 gxf6 23.Ne4 Re6 24.Qxh6 Ra5 25.Nf2 d3 26.Rd1 f5 27.Qf4 Rd5 28.Qxf5 d2 29.Qc2 b5 30.b3 Rc6 31.Qe4 Re6 32.Qc2

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Analysis by Stockfish 2.0.1 JA 64bit (30-ply):

1. = (0.00): 22.Qd3 Ra5 23.Rxe8+ Qxe8 24.Bxf6 gxf6 25.Nxd5 Qe5 26.Nxf6+ Qxf6 27.Qxc4 Qxb2 28.Rd1 Kg7 29.Rd7 Qa1+ 30.Kf2 Qb2+ 31.Kf1 Qa1+ 32.Kf2

2. = (0.00): 22.Qd4 Rxe1 23.Rxe1 Nxb2 24.a4 Qd6 25.Kh1 Nc4 26.Bxf6 Qxf6 27.Qd3 Qg6 28.Qxd5 Nd6 29.Qa8+ Kh7 30.Nd5 f5 31.Nf4 Qf7 32.Ne6 Rxa4 33.Nf8+ Kg8 34.Nd7+ Kh7 35.Nf8+

3. = (0.00): 22.Qc1 b5 23.Rxe8+ Qxe8 24.Rd1 Rd6 25.Bxf6 gxf6 26.Qxh6 Nxb2 27.Qf4 Nxd1 28.Qg3+ Kh7 29.Qh3+ Kg7 30.Qg3+ Kh6 31.Qh4+ Kg6 32.Qg4+ Kh7 33.Qh3+

4. ³ (-0.32): 22.Rxe8+ Qxe8 23.Qd4 Qe3+ 24.Qxe3 Nxe3 25.Rc1 d4 26.Bxf6 gxf6 27.Nd1 Nf5 28.Rc4 Ra5 29.g4 Nh4 30.Kf2 Rd5 31.Rc7 f5 32.Rxa7 Kg7 33.h3 Ng6 34.Ra6 fxg4 35.hxg4 b5 36.a4 bxa4 37.Rxa4 h5

5. ³ (-0.36): 22.Qf2 b5 23.Qc5 Rxe1 24.Rxe1 Qb6 25.Qxb6 Rxb6 26.Bxf6 Rxf6 27.Nxd5 Rd6 28.Nc7 a6 29.Re8+ Kh7 30.Re2 Rc6 31.Nd5 Rc5 32.Nb4 a5 33.Na2 Kg6 34.Kf2 f6 35.Rc2 a4 36.Re2 Kf7 37.Nb4 Re5

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Analysis by Stockfish 2.0.1 JA 64bit (31-ply):

1. = (0.00): 22.Qd4 Qb8 23.Bg3 Rae6 24.Nxd5 Nxd5 25.Qxd5 Qb6+ 26.Bf2 Qb8 27.Qd4 a6 28.Bg3 R8e7 29.Re4 Qe8 30.Rfe1 Nc4 31.a4 Rxe4 32.Rxe4 Rxe4 33.fxe4 Qc8 34.axb5 axb5 35.h4 Qf8 36.b3 Na5 37.Qc3 Qa3

2. = (0.00): 22.Bxf6 Rxf6 23.Qxd5 Qb8 24.f4 Nc4 25.Qxb5 Qxb5 26.Nxb5 Rxe1 27.Rxe1 a6 28.Nc7 Nxb2 29.g3 Nc4 30.a4 Rc6 31.Nd5 Rd6 32.Rc1 Nb2 33.Ne7+ Kh7 34.a5 Rd2 35.Rc6 Nd3 36.h3 Ne1 37.Rxa6 Nf3+

3. = (-0.16): 22.b3 b4 23.axb4 Qb6+ 24.Bf2 Qxb4 25.Qd4 Qxd4 26.Bxd4 Rae6 27.Ra1 Nc6 28.Bxf6 Rxf6 29.Nxd5 Rd6 30.Rfd1 Red8 31.Ra6 Kh7 32.Rxc6 Rxc6 33.Nf6+ Kg6 34.Rxd8 Kxf6 35.Kf2 g6 36.Rd3 Rc7 37.f4 Ke6

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Analysis by Stockfish 2.0.1 JA 64bit (33-ply):

1. = (0.00): 23...Qc6 24.Qxd4 Ra4 25.Qd6 Rc4 26.b3 Rc2 27.Qxc6 Rxc6 28.Rd1 Re7 29.Rfe1 Rc2 30.Ng3 g6 31.f4 Nc6 32.Rxe7 Nxe7 33.Rd7 Nc6 34.f5 Kg7 35.fxg6 Kxg6 36.h4 Kf6 37.Rd6+ Ke5 38.Rxh6 Nd4 39.Kh2

2. = (0.00): 23...Qd8 24.f4 Ng4 25.Qe2 Ra5 26.Qxg4 Rxe4 27.Rxe4 f5 28.Qh3 fxe4 29.Qe6+ Kf8 30.Qxe4 d3 31.Rd1 Rd5 32.g3 Qd7 33.Rd2 Rd4 34.Qe5 Kf7 35.Kf2 Rd5 36.Qe4 Rd4 37.Qe5

3. = (0.20): 23...Qg6 24.Qxd4 Ra5 25.f4 Qc6 26.h3 Ng6 27.Nc3 Rc5 28.Rxe8+ Qxe8 29.Rd1 Rc8 30.g3 Qe6 31.Kh2 Ne7 32.h4 Nf5 33.Qd7 Qxd7 34.Rxd7 a5 35.Kh3 Ne3 36.Nd5 Nxd5 37.Rxd5 Rc6 38.Kg4 g6 39.h5

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Analysis by Stockfish 2.0.1 JA 64bit (32-ply):

1. = (0.12): 26.f4 Ng4 27.Nc3 Qxd4+ 28.Rxd4 Ne3 29.Rf2 Rc5 30.h3 Nc4 31.Ne4 Rcc6 32.Rc2 Na5 33.Rd8+ Kh7 34.Nc3 Rc7 35.g3 g6 36.Kf2 Kg7 37.Rcd2 Nc4 38.Nd5 Rc5 39.Rc2 Rxd5 40.Rxd5 Ne3 41.Rdd2 Nxc2

2. = (0.08): 26.Ne3 Qxd4 27.Rxd4 Nc6 28.Rd3 Ne5 29.Rd2 Rc5 30.Kf2 Nc4 31.Nxc4 Rxc4 32.g4 Kh7 33.Kg3 Kg6 34.h4 Rc7 35.Rfd1 Kf6 36.h5 Ree7 37.Rd6+ Re6 38.R6d3 Rc2 39.b3 a6 40.a4 Rc7

3. = (0.08): 26.h3 Nc6 27.Qd2 Rc5 28.Nf4 Qxd2 29.Rxd2 Re8 30.Nd5 Ne5 31.Ne3 Kh7 32.Kf2 Nc4 33.Nxc4 Rxc4 34.g4 Kg6 35.Kg3 Rc7 36.Rfd1 Kf6 37.Rd7 Rxd7 38.Rxd7 Re7 39.Rxe7 Kxe7 40.Kf4 Ke6

4. = (0.00): 26.Rf2 Rc5 27.Ne3 Qxd4 28.Rxd4 Rc1+ 29.Rf1 Rxf1+ 30.Nxf1 f5 31.Ng3 g6 32.h4 Kf7 33.h5 Rc6 34.hxg6+ Kxg6 35.b3 Rc1+ 36.Kf2 Rc2+ 37.Ne2 Rb2 38.Rd6+ Kg7 39.Rd5 Kf6 40.Rd6+ Kg7

5. = (0.00): 26.Qe4 Rd6 27.Ne3 Nd3 28.Nf5 Rd7 29.Ne7+ Qxe7 30.Qxe7 Rxe7 31.Rxd3 Rc5 32.Rd8+ Kh7 33.Rd2 Kg6 34.Kf2 Kf6 35.Rfd1 Rec7 36.f4 Rc2 37.Ke3 Ke6 38.Rd6+ Ke7 39.R6d2 g6 40.Kf3 Rxd2 41.Rxd2 Rc4

6. = (0.00): 26.Rd2 Nc6 27.Qd3 Ne5 28.Qd4

7. = (0.00): 26.Nc3 Qxd4+ 27.Rxd4 Rc5 28.a4 Kh7 29.Rc1 g5 30.Kf2 Kg6 31.Rcd1 Rc8 32.Nd5 Rc2+ 33.R1d2 Nc6 34.R4d3 Ne5 35.Rd4

8. = (0.00): 26.Nf4 Qxd4+ 27.Rxd4 Rc6 28.Rd2 Rac5 29.Kf2 g5 30.Ne2 Nc4 31.Rc2 Ne5 32.Rd2

9. = (0.00): 26.Nb4 Qxd4+ 27.Rxd4 Rc5 28.Rfd1 g5 29.Kf2 Kg7 30.R1d2 Nc4 31.Nd3 Rcc6 32.Rc2 Ne5 33.Rd2 Nc4

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Analysis by Stockfish 2.0.1 JA 64bit (34-ply):

1. = (0.00): 26...Qxd4 27.Rxd4 Nc6 28.Rd3 Ne5 29.Rd2 Nc4 30.Nxc4 Rxc4 31.Kf2 f5 32.Rfd1 Kf7 33.Rd7+ Re7 34.R1d2 Rc7 35.R7d5 Kf6 36.f4 Re6 37.Kf3 g5 38.Rd7 Rc4 39.g3 a5 40.Rh7 Kg6 41.Rhd7 Kf6

2. = (0.00): 26...Qc7 27.b4 Nc6 28.Qg4 Rg5 29.Nd5 Qb8 30.Qc4 Ne7 31.Nc3 Nf5 32.Nd5 Ne7

3. = (0.00): 26...Qc8 27.Rfe1 Nc4 28.Nf1 Re6 29.Rxe6 fxe6 30.Ne3 Nxe3 31.Qxe3 Rc2 32.Rd2 Rxd2 33.Qxd2 Qc5+ 34.Kf1 Kf8 35.b4 Qc4+ 36.Kf2 Qh4+ 37.Kg1 Ke7 38.Qc3 Kd6 39.Qd3+ Ke7 40.Qc3

4. = (0.00): 26...Rc8 27.f4 Qxd4 28.Rxd4 Nc6 29.Rd3 Na5 30.g3 Nc4 31.Nxc4 Rxc4 32.Rf2 Re7 33.Kg2 f6 34.Rfd2 Kf7 35.Kf2 g6 36.Rd6 Rc1 37.g4 Rh1 38.Kg2 Rhe1 39.Kf2 Rh1

5. = (0.00): 26...Qe7 27.Rfe1 Qf6 28.f4 Ng4 29.Qxf6 Nxf6 30.g3 g6 31.Kg2 Rb5 32.Rd2 Rb3 33.Rde2 Rd3 34.Nc4 Rc8 35.Ne5 Rdd8 36.Kf3 Kg7 37.g4 Rd4 38.Ke3 Re4+ 39.Kf3 Rd4

6. = (0.20): 26...Qf6 27.f4 Nd7 28.Rfe1 Re7 29.g3 Qxd4 30.Rxd4 Rc8 31.Kf2 Rce8 32.Kf3 g6 33.g4 Kg7 34.Rd6 Nf6 35.Rxf6 Rxe3+ 36.Rxe3 Rxe3+ 37.Kxe3 Kxf6 38.Ke4 Ke6 39.h3 Kd6 40.f5 a5 41.Kd4 gxf5 42.gxf5

7. = (0.24): 26...Qd7 27.Qxd7 Nxd7 28.Kf2 Nf6 29.h4 h5 30.Rd4 Kf8 31.Rfd1 Rce5 32.R1d3 g6 33.b3 Kg8 34.b4 Kg7 35.Rc3 b5 36.Rdd3 a6 37.Rc6 R5e6 38.Rxe6 Rxe6 39.Rd8 Rc6 40.Ke2 Rc3

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Analysis by Stockfish 2.0.1 JA 64bit (33-ply):

1. = (0.00): 27.Kf2 Rc6 28.Rg1 Rce6 29.Rge1 Qc6 30.f4 Ng6 31.g3 Re4 32.Qc3

2. = (0.00): 27.b4 Rc6 28.Nd5 Rc4 29.Qe3 Rc2 30.Rfe1 Kf8 31.Qe4 Ra2 32.Qh7 Ng6 33.Nf4 Rxe1+ 34.Rxe1 Qd7 35.Nxg6+ fxg6 36.Qxg6 Rxa3 37.Qe4 Rd3 38.Qf4+ Kg8 39.Qc4+ Kf8 40.Kf2 Rd2+ 41.Re2 Rxe2+ 42.Kxe2 Qe7+

3. = (0.00): 27.Rfe1 Nc4 28.Kf2 Nxe3 29.Rxe3 Rc2+ 30.Rd2 Rxd2+ 31.Qxd2 Rxe3 32.Qxe3 Qc2+ 33.Qe2 Qc5+ 34.Qe3 Qc2+

4. = (-0.08): 27.h3 Nc4 28.Nd5 Rxd5 29.Qxd5 Ne3 30.Qd2 Nxd1 31.Rxd1 Qc5+ 32.Kf1 Qc4+ 33.Kf2 h5 34.Re1 Rxe1 35.Kxe1 h4 36.b3 Qe6+ 37.Kf2 f6 38.Qd8+ Kf7 39.Qc7+ Kg6 40.Qf4 Kh5 41.Qg4+ Qxg4 42.fxg4+ Kg6

5. = (-0.12): 27.f4 Ng4 28.Nxg4 Qxg4 29.h3 Qf5 30.Rf2 Rc7 31.Qd5 Qf6 32.Kh2 Rce7 33.Rdd2 Kh7 34.Qd6 Qxd6 35.Rxd6 f6 36.Rdd2 h5 37.Kg3 Re3+ 38.Rf3 Re2 39.Rxe2 Rxe2 40.Rf2 h4+ 41.Kf3 Rxf2+ 42.Kxf2 Kg6

6. = (-0.12): 27.Qd2 Nc4 28.Nxc4 Rxc4 29.Rf2 Rc7 30.Re2 Rxe2 31.Qxe2 Rc2 32.Rd8+ Qxd8 33.Qxc2 Qd4+ 34.Kf1 g5 35.g3 Kf8 36.Ke2 Qe5+ 37.Kd2 Ke7 38.Qc3 Kd6 39.Qxe5+ Kxe5 40.Ke3 h5 41.f4+ gxf4+ 42.gxf4+ Kd5

7. = (-0.20): 27.Nd5 Rc4 28.Qe3 Rc2 29.Rf2 Rxf2 30.Qxf2 Nd3 31.Qd4 Qc2 32.Ne7+ Rxe7 33.Qd8+ Kh7 34.Qxd3+ Qxd3 35.Rxd3 Re2 36.b3 Kg6 37.Rd7 Re3 38.Rxa7 Rxb3 39.Kf2 Rb2+ 40.Kg3 Kf6 41.Rb7 Ke6 42.a4 Rb4

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Analysis by Stockfish 2.0.1 JA 64bit (32-ply):

1. = (0.00): 27...Nc6 28.Rd3 Ne5 29.Rd2 Nc4 30.Nxc4 Rxc4 31.Kf2 Re7 32.g4 f5 33.gxf5 Rc5 34.f6 gxf6 35.f4 Kf7 36.Kf3 Rc4 37.Rg1 Ree4 38.Rg4 Ke6 39.Rh4 Kf5 40.Rd5+ Ke6 41.Rd2

2. = (0.04): 27...Kf8 28.f4 Nc6 29.Rd3 Nd4 30.g3 Nc2 31.Ng2 Rc4 32.Rfd1 Rce4 33.Rd7 R8e7 34.R7d6 Re8 35.Kf1 Re2 36.R1d2 Rxg2 37.Kxg2 Ne3+ 38.Kf3 Nc4 39.Rd7 Nxd2+ 40.Rxd2 Rc8 41.Re2 f5 42.h3 Rc1 43.Ke3

3. = (0.08): 27...f6 28.Kf2 Nc6 29.Rd2 Ne5 30.Re1 Nc4 31.Rc2 Rec8 32.Nxc4 Rxc4 33.Re8+ Rxe8 34.Rxc4 Kf7 35.Rc7+ Re7 36.Rxe7+ Kxe7 37.Ke3 f5 38.Kd4 Ke6 39.b3 Kd6 40.Kc4 a6 41.Kd4 Ke6 42.f4

4. = (0.12): 27...Rcc8 28.Kf2 Nc6 29.Rd5 Ne5 30.Rfd1 Nc4 31.Nxc4 Rxc4 32.R1d2 Re7 33.Rd8+ Kh7 34.R8d7 Rc7 35.R7d5 g5 36.Rd6 Kg7 37.h4 gxh4 38.R6d4 h3 39.gxh3 Rc6 40.f4 Kf6 41.Kf3 Rce6 42.Kg4 Re3

5. = (0.12): 27...Rec8 28.Rfd1 g6 29.h3 Kg7 30.Re4 b5 31.b4 f5 32.bxc5 fxe4 33.Rd5 Nd3 34.Rd7+ Kf8 35.fxe4 Nxc5 36.Rxa7 Nxe4 37.Ng4 Rc1+ 38.Kh2 h5 39.Ne5 g5 40.Rb7 Rc3 41.Rxb5 Rxa3 42.Rb7 Ra2 43.Nf3

6. = (0.20): 27...a5 28.f4 Nc6 29.Rd3 Re4 30.g3 g5 31.Nd5 Re2 32.Nc3 Re6 33.Rd7 gxf4 34.Rxf4 Ne5 35.Rdd4 Kg7 36.Kg2 Ng6 37.Rf2 Ne5 38.Kh3 Nc4 39.Rg4+ Kf8 40.Rgf4 Ne5 41.Kg2

7. = (0.20): 27...g6 28.Kf2 Nc6 29.Rd2 Kg7 30.Re1 Ne5 31.Rd4 h5 32.Re2 Nc6 33.Rd1 Rce5 34.Rd3 R5e6 35.Red2 b5 36.Rd6 Rxe3 37.Rxc6 R8e7 38.Rcd6 R3e5 39.R6d4 g5 40.f4 gxf4

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Analysis by Stockfish 2.0.1 JA 64bit (32-ply):

1. = (0.00): 27...Qc8 28.f4 Nc6 29.f5 Kh7 30.b3 Rc5 31.b4 Rc4 32.f6 g6 33.Qa2 b5 34.Qf2 Qd8 35.Rfe1 Rxe1+ 36.Qxe1 Rd4 37.Rxd4 Nxd4 38.Qe5 Nc6 39.Qe4 a6 40.Kh1 Qd6 41.Ne7 Qd1+ 42.Kh2 Qd6+ 43.Kh1

2. = (0.00): 27...Rc6 28.Qd4 Rc4

3. = (0.00): 27...Rc5 28.Qd4

4. = (0.08): 27...Qb8 28.f4 Nc6 29.Rfe1 Rce4 30.Rxe4 Rxe4 31.Qf3 Qe8 32.Nc3 Rd4 33.Kf2 Qd7 34.Rxd4 Qxd4+ 35.Qe3 Qd7 36.Qe4 f5 37.Qc4+ Kh7 38.Nd5 Ne7 39.Nxe7 Qxe7 40.Qd5 Kg6 41.Kf3 Qf7 42.Qxf7+ Kxf7 43.Ke3

5. = (0.12): 27...Kh7 28.f4 Ng6 29.f5 Ne5 30.f6 g6 31.Ne7 Qc7 32.Rfe1 Nc6 33.Qf1 b5 34.b3 Rc5 35.Nd5 Rxe1 36.Qxe1 Qb8 37.Qe3 Rc2 38.Qe4 Rc5 39.Kh1

6. = (0.20): 27...Ng6 28.f4 Rc5 29.Nc3 Qc8 30.Qd2 Rf5 31.Kh2 h5 32.Nd5 Ne7 33.Rc1 Qb8 34.Nxe7+ Rxe7 35.Rc4 Rc5 36.Rd4 Kh7 37.Qd3+ g6 38.Rd6 Qh8 39.f5 Qe5+ 40.Kg1 gxf5 41.b4 Rc3 42.Qxf5+ Qxf5

7. = (0.24): 27...Nc6 28.Rd2 Na5 29.Re1 Rxe1+ 30.Qxe1 Nc6 31.Qd1 Qh4 32.Kh2 Rd4 33.Rxd4 Qxd4 34.Qxd4 Nxd4 35.Kg3 f6 36.Kf4 Kf7 37.Ke4 Nb3 38.Nc7 Nc5+ 39.Ke3 Ke7 40.Nb5 a5 41.f4 Kd7 42.Nd4 Na4 43.b3

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Analysis by Stockfish 2.0.1 JA 64bit (30-ply):

1. = (0.00): 29.Qd4 Qxh3 30.Ne7+ Kf8 31.Ng6+ Kg8 32.Ne7+

2. = (0.00): 29.Qb4 Ng6 30.Ne3 Rc5 31.Kf2 Qc6 32.Qg4 Qb5 33.Qb4 Qc6

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Analysis by Stockfish 2.0.1 JA 64bit (30-ply):

1. = (0.00): 29...Rc4 30.Qe3 Rc5 31.f4 Rxd5 32.Rxd5 Nf3+ 33.Qxf3 Rxe1+ 34.Kf2 Re8 35.Qd3 Qc1 36.Qd2 Qc4 37.Rd7 Re4 38.g3 Qc5+ 39.Kf3 Re3+ 40.Qxe3 Qc6+ 41.Kf2 Qxd7 42.h4 f5 43.h5 Kh7 44.Qe5 Qd2+ 45.Qe2

2. = (0.00): 29...Ng6 30.Ne3 Rc6 31.Kf2 Rc5 32.Qd7 Qb8 33.Qd6 Qc8 34.Qd7

3. = (0.00): 29...Nc6 30.Qd3 Ne5 31.Qb3 Qc5+ 32.Ne3 Rc4 33.Kf1 Rd4 34.Rc1 Qa5 35.Nf5 Rdd8 36.Rcd1 Qa6+ 37.Kf2 Rxd1 38.Rxd1 Qc8 39.g4 Ng6 40.Qb4 Qc2+ 41.Rd2 Qc1 42.Qd4 Qe1+ 43.Kg2 Nf4+ 44.Qxf4 Re2+ 45.Rxe2

4. = (0.00): 29...Qxh3 30.Ne7+ Kf8 31.Ng6+ Kg8 32.Ne7+

5. = (0.08): 29...Qf5 30.Qe4 Qxe4 31.Rxe4 Re6 32.Nf4 Re7 33.b3 f6 34.Nd5 Rb7 35.f4 Ng6 36.Kf1 Rb2 37.Rd3 Kf7 38.Re2 Rb1+ 39.Kf2 Rd7 40.Red2 Ne7 41.Nxe7 Rxd3 42.Rxd3 Kxe7 43.f5 Rc1 44.g3 h5 45.Kf3

6. = (0.08): 29...f6 30.Kh1 Ng6 31.Rxe8+ Qxe8 32.Ne3 Rc7 33.Kg1 Qe5 34.Kf2 Kf7 35.Qxe5 fxe5 36.Rd6 Nf4 37.h4 Ke7 38.Rd1 Ke6 39.Rd8 Rd7 40.Rxd7 Kxd7 41.Nf5 Nd3+ 42.Ke2 Nf4+ 43.Kf1 Ne6 44.h5 Kc6 45.Kf2

7. = (0.12): 29...Qc5 30.Qxc5 Rxc5 31.Kf2 Kf8 32.b3 Ng6 33.Rxe8+ Kxe8 34.Rd3 f5 35.f4 Kf7 36.g3 Ne7 37.Nc3 a6 38.b4 Rc8 39.Kf3 b5 40.Ne2 Rc2 41.g4 Ra2 42.Nd4 g6 43.Kg3

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Analysis by Stockfish 2.0.1 JA 64bit (33-ply):

1. = (-0.20): 29...Ng6 30.Ne3 Rc5 31.Qa4 Rce5 32.Qd4 Kh7 33.Kf1 Qe6 34.Nc2 Qb3 35.Rxe5 Nxe5 36.Re1 Nc6 37.Qc3 Qxc3 38.bxc3 Rc8 39.Nb4 g5 40.Re4 Nxb4 41.cxb4 Rc3 42.Re7 Rxa3 43.Rxf7+ Kg6 44.Rc7

2. = (0.00): 29...Kh7 30.Ne3 Nxf3+ 31.gxf3 Qxh3 32.Nxc2 Qg3+ 33.Kh1 Qh3+ 34.Kg1

3. = (0.00): 29...Rc5 30.Qh4 Ng6 31.Rxe8+ Qxe8 32.Qf2 Rc8 33.Qe3 Qb5 34.b4 Re8 35.Qd3 Qxd3 36.Rxd3 Re2 37.g3 h5 38.h4 Ne5 39.Kf1 Ra2 40.Rc3 Kh7 41.Ke1 Ra1+ 42.Kf2 Ra2+ 43.Ke1

4. = (0.00): 29...Nc6 30.Rxe8+ Qxe8 31.Re1 Re2 32.Rxe2 Qxe2 33.Qd6 Ne5 34.Ne7+ Kh7 35.Qd8 Qe1+ 36.Kh2 Nxf3+ 37.gxf3 Qf2+ 38.Kh1 Qxf3+ 39.Kh2 Qf2+ 40.Kh1 Qf3+

5. = (0.00): 29...Qf5 30.Qe4 Qxe4 31.Rxe4 Re6 32.Nf4 Rf6 33.b3 Rb2 34.b4 Ng6 35.Re2 Rb3 36.Rd8+ Kh7 37.Nd5 Re6 38.Ra2 Ne5 39.Kh2 Rg6 40.Nf4 Rc6 41.Nd5 Rg6

6. = (0.00): 29...Qc6 30.Qe4 Kf8 31.b3 Ra2 32.Qb4+ Kg8 33.Qe4 Kf8

7. = (0.00): 29...Qxh3 30.Nf6+ gxf6 31.gxh3 Nxf3+ 32.Kf1 Nh2+ 33.Kg1 Rxe1+ 34.Rxe1 Nf3+ 35.Kf1 Nh2+ 36.Kg1

8. = (0.04): 29...Kh8 30.Qb3 Re6 31.Nf4 Re7 32.Kh1 Kh7 33.Re3 Rc1 34.Nd5 Re6 35.f4 Rxd1+ 36.Qxd1 Nc6 37.Rc3 g6 38.Kh2 Rd6 39.Nxb6 Qe6

9. = (0.08): 29...Qe6 30.Kf1 Qg6 31.Rd2 Rxd2 32.Qxd2 Qc6 33.Re2 Ng6 34.Rxe8+ Qxe8 35.Qd4 Qc6 36.Nc3 f6 37.Qe4 Ne5 38.Qxc6 Nxc6 39.Ke2 Kf7 40.Nb5 Ke6 41.f4 Kd5 42.Kd3 g5 43.Nc3+ Ke6 44.fxg5 hxg5

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1. [0.00], d=27: 29...Rc4 30.Qe3 Re6 31.b4 <Kh8> 32.Qb3 Ng6 33.Qd3 Rxe1+ 34.Rxe1 <Rc2> 35.f4 <Rc1> 36.Rd1 Rxd1+ 37.Qxd1 Qf5 38.Qd4 <Kh7> 39.Qc4 b5 40.Qd4 <Qc2>

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<31…Kh8> While it exposes our king more, 31…Kf8 brings our king closer to the center where it will need to be in the endgame. And why is it needed at all? The immediate 31…Ng6 guards against the knight fork at e7.

<34…Rc2> 34…Nf4 eliminates the pesky Nd5, White’s best placed piece and reduces to a K+Q+P endgame.

<35…Rc1> And this shows that 34..Rc2 was a waste of a tempo.

<38…Kh7> And, of course, 31…Kh7 would have saved a tempo.

<40..Qc2> Critter assesses the position as no worse than even for Black after 41.Nc3 at d=27, but it didn’t evaluate the consequences of 41…Qc1+ 42.Kh2 Qxa3, seemingly winning a pawn. And Black’s play can be improved by not wasting several tempos.

2. [0.00]D, d=27: 29...Ng6 30.Ne3 Rc6 31.<Kf2> Rce6 32.Rc1 Qb8 33.Nf5 Ne5 34.Rcd1 Qc7 35.Rc1 <Qb8>

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<31.Kf2> White’s king looks a little exposed here but this is needed to provide protection to the Re1 after Black doubles rooks on the e-file.

<35…Qb8> Critter is apparently headed to a draw by repetition in an apparently even position.

3. [0.00], d=27: 29...Qxh3 30.Ne7+ Rxe7 31.Qd8+ Kh7 32.gxh3 Nxf3+ 33.Kf1 Nh2+ 34.Kg1 <Nf3+>

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<34…Nf3+> The now-familiar queen sac to achieve a draw by repetition. And this line with 30.Ne7+ shows how Black’s life hangs by a thread; not only is he down a queen but is faced with a loss of the exchange after Qxe7 or Rxe7, and Black’s Rc2 is potentially in danger of being picked off with Qd3+. But it’s a tough thread.

4. [+0.03], d=27: 29...Qf5 30.Qe4 Qxe4 31.Rxe4 <Re6> 32.Nf4 Rf6 33.b4 Kh7 34.Re2 Rxe2 35.Nxe2 <g5> 36.Rd4 Rc6 37.f4 gxf4 38.Nxf4 Rc3 39.a4 Ra3 40.b5 <Kg7>

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<31…Re6> Black unfortunately has no time for 31…Rxb2 because of 32.f4.

<35…g5> This seems like an unnecessary weakening just to try to prevent a possible Nf4 by White (which, BTW, doesn’t work). The immediate 35…Rc6 seems better.

<40…Kg7> And White has the better endgame because of his superior pawn structure but I don’t think it’s enough to win.

5. [+0.04], d=27: 29...Qc5 30.Qxc5 Rxc5 31.Re3 Kf8 32.b3 f6 33.f4 Ng6 34.Rxe8+ Kxe8 35.Rd3 Kf7 36.g3 Ne7 37.Ne3 Ke6 38.Kf2 Rc8 39.a4 g6 40.Kf3 <Rc1>

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All these lines, even some of those that are evaluated to be in White’s favor are, in reality, no worse than even for Black.

1. [0.00], d=35: 29...Qxh3 30.Ne7+ Rxe7 31.Qd8+ Kh7 32.gxh3 Nxf3+ 33.Kf1 Rxe1+ 34.Rxe1 Nh2+ 35.Kg1 Nf3+ 36.<Kf1>

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<36.Kf1> The standard queen sac/perpetual line with a slight twist in 33…Rxe1+. Leave it to Spike to be a little bit more creative in extending the horizon effect than Critter!

2. [0.00]D, d=35: 29… Ng6 30.Rxe8+ Qxe8 31.Ne3 Re2 32.Nf5 <Qe5> 33.Qxe5 Nxe5 34.Rd8+ Kh7 35.f4 Nc4 36.Rd7 Rxb2 37.Rxa7 Kg6 38.Ne7+ Kh7 <39.Nf5>

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<32…Qe5> The queen exchange can’t be avoided since if, for example, 32…f6, then 33.Qd8. Then White gets a small advantage after 33…Qxd8 34.Rxd8+ Kf7 35.Ra8 a5 36.Ra7+ Kf8 37.Rxg7. And 32…Ne4 loses to 33.f4. Black could consider an exchange of rooks first by 32…Re1+ 33.Rxe1 Qxe1+ 34.Kh2 Qe5+ 35.Qxe5 Nxe5. But after 36.b3 Critter evalutates the position as slightly better for White.

<39.Nf5> And apparently Spike is going for a draw by repetition. 38…Kf6 suffers the same fate after 39.Ng8+ Kg6 40.Ne7+. And, per Critter, 39…Ke6 40.Re7+ is slightly to White’s advantage as an interesting pawn race ensues as Black gives up two of its k-side pawns and White gives up it’s a-pawn. But the final position is a Nalimov tablebase draw.

3. [+0.04], d=35: 29...Rc4 30.Qe3 Re6 31.<b4> Ng6 32.Qd3 Rxe1+ 33.Rxe1 Kf8 34.Qe3 Qd7 35.Rd1 <Rc8> 36.f4 <Ne7> 37.Qf3 Qc6 38.Rd3 Re8 39.Nxe7 Qxf3 40.<Rxf3> Kxe7 41.Re3+ Kd7 42.<Rg3> g6 43.Rd3+ Kc6 44.Rc3+ <Kd7> 45.Kf2 b5 46.Rd3+ Kc6 47.Kf3 a6 48.f5 h5 49.Rc3+ Kd7 50.f6 <Re6>

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<31.b4> Necessary, otherwise Black has nasty checks along the a7-g1 diagonal in conjunction with …Ng4.

<35…Rc8> This may be a little too passive since Black’s back rank is not currently in danger. 35…Rc6 with the idea of 36…Re6 looks more active.

<36…Ne7> Black’s pieces have gradually been driven back and White now commands more space.

<40.Rxf3> 40.Ng6+ to first double Black’s pawns and then 41.Rxf3 seems better.

<42.Rg3> The K+P endgame after 42.Rxe8 Kxe8 is advantageous for Black since the Black king gets to the q-side pawns faster than White’s king, even after 43.Kf2.

<44…Kd7> With the White king cut off from the q-side it seems that 44…Kb5 is more active, sacrificing the k-side pawns to advance the q-side pawns. Critter evaluates the position at [0.00] at d=25 after either 45.Rd7 or 45.Kf2 but I don’t know if it’s able to search deep enough in the endgame; forward sliding would be necessary.

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4. [+0.10], d=34: 29...Qc5 30.Qxc5 Rxc5 31.Kf2 Kf8 32.b3 Ng6 33.Rxe8+ Kxe8 34.b4 Rc2+ 35.Kg3 f5 36.h4 h5 37.Rd4 Ra2 38.Rc4 Rxa3 39.Rc7 Kf8 40.<Nf4> Nxf4 41.Kxf4 a5 42.bxa5 Rxa5 43.Rb7 Rb5 44.Kg5 Rb2 45.g3 <Rg2> 46.Rxb6 Rxg3+ 47.Kxf5 Rg2 48.Rb7 Kg8 49.f4 <Kh7>

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<40.Nf4> Excellent move by White. After the knight exchange White’s king can penetrate into the k-side pawns and Black’s king is cut off from their defense by White’s rook on the 7th rank.

<45…Rg2> But this basically concedes the draw. Black’s only winning (and losing!) chances require keeping the b-pawn.

<49…Kh7> And this is a clear draw.

5. [+0.13], d=34: 29...Qf5 30.Qe4 Qxe4 31.Rxe4 <Re6> 32.Nf4 Rf6 33.b3 Ng6 34.Re2 Rfc6 35.Rxc2 Rxc2 36.Nxg6 fxg6 37.Rd7 Rc3 38.Rxa7 Rxb3 39.h4 Kh7 40.Kh2 b5 41.Kg3 Rc3 42.Rb7 <Rb3> 43.Rb6 Rxa3 44.Rxb5 Ra2 45.Rb3 Rd2 46.Kh3 Ra2 47.g4 Ra4 48.Kg3 Rd4 49.Rb7 h5 50.<g5>

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<31…Re6> 31…Kf8 protecting the rook and unpinning the knight might be better since Black will probably need to make this move anyway to centralize its king.

<42…Rb3> Critter, at d=28, surprisingly evaluates the position (which transposes into the main line) after 42…Rxa3 43.Rxb5 as slightly advantageous for Black ([-0.12]).